S  B     • 
951 
C32 
Lntomol. 


IC-NRLF 


STATE  HORTICULTURAL  COMMISSION 

^  -    • 

ELLWOOD  COOPER,  Commissioner 


INSECTS    AND 
INSECTICIDES 


ra*. 


FEB   3  1958 


W.  W.  SHANNON, 


SACRAMENTbJ^JY^'TY  OF  CAL' 

SUPT.  STATE  PRINTING 


1905 


CALIFORNIA  STATE.  COMMISSION  OF 
HORTICULTURE. 


ELLWOOD  COOPER Commissioner Santa  Barbara. 

JOHN  ISAAC Secretary San  Francisco. 

ED.  M.  EHRHORN Deputy Mountain  View. 

E.  K.  CARXES Assistant  Deputy Riverside. 

O.  E.  BREMXER Second  Assistant Santa  Rosa. 

GERTRUDE  BIRD Stenographer Sacramento. 


OFFICE: 

ROOM  41,  STATE  CAPITOL,  SACRAMEJETO. 
BRANCH  OFFICE,  ROOM  11,  FERRY  BUIUHKG,  SAX  FRANCISCO. 


//?  t 

IN5LCT5  AND  IN5LCTICIDL5. 


In  order  to  intelligently  apply  insecticides,  and  to  be  able  to 
judge  whether  one  remedy  or  another  will  be  more  effective,  it 
is  necessary  to  understand  something  of  the  habits  of  the 
different  insects  attacking  plants.  Many  insects,  like  cater- 
pillars, grasshoppers,  and  beetles,  devour  the  foliage,  while 
others,  such  as  scale  insects,  plant  lice,  squash  bugs,  etc.,  injure 
the  plant  by  inserting  their  sharp  beaks  into  its  tissue  and 
sucking  the  sap  from  beneath  the  surface.  Insects  of  the  first 
class  can  nearly  always  be  destroyed  by  means  of  poisons, 
such  as  paris  green  and  various  forms  of  arsenates.  Those  of 
the  second  class,  or  sucking  insects,  are  unaffected  by  these 
poisons  and  must  be  killed  by  contact  sprays,  such  as  kerosene 
emulsion,  whale-oil  soap,  crude-oil  mixtures,  or  the  lime-sul- 
phur-salt remedy.  Another  class  of  insects,  and  which  none 
of  the  above  remedies  will  reach,  are  those  which  burrow  into 
the  bark  and  trunks  of  trees.  These  must  be  treated  mechan- 
ically— dug  out,  and  barriers  or  repellants  provided  to  prevent 
them  from  regaining  entrance  into  the  trees.  In  the  following 
pages  the  most  successful  remedies  are  given,  but,  under  cer- 
tain climatic  conditions  or  in  abnormal  seasons,  other  steps 
may  become  necessary  and  advice  from  the  State  Commission 
of  Horticulture  should  always  be  obtained  in  cases  where  any 
doubt  exists. 

It  should  be  remembered  that  the  successful  application  of 
remedies  is  dependent  upon  the  exercise  of  proper  judgment. 
It  is  essential  to  first  positively  identify  the  insect  to  be 
destroyed,  then  to  know  the  most  effective  remedy  to  use,  and 
finally  to  apply  it  at  the  proper  season.  Promptness,  thor- 
oughness, and  persistency,  combined  with  good  judgment,  are 
the  essential  factors  necessary  for  the  successful  application  of 
insecticides. 

This  office  is  at  all  times  glad  to  render  any  assistance  pos- 
sible in  determining  the  identity  of  insects  and  in  advising  as 
to  the  remedy  to  be  used  for  their  control.  Insects  should  not 


908 


STATE   HORTICULTURAL   COMMISSION. 


be  sent  by  mail  in  envelopes  or  pasteboard  boxes,  as  they  are 
almost  invariably  crushed  beyond  recognition ;  strong  wooden 
or  tin  boxes  should  be  used.  Openings  to  admit  air  are  not 
necessary.  Plant  specimens,  showing  the  injury  done,  are 
desirable.  The  name  and  address  of  the  sender  should  be  on 
every  package.  It  will  help  greatly  if  correspondents,  when 
writing  about  insect  pests,  will  give  as  full  a  description  of 
the  habits,  food  plants,  injury  and  abundance  as  possible. 
Specimens  of  twigs,  living  plants  with  foliage,  etc.,  should  be 
wrapped  in  damp  (not  wet)  cotton  cloths  so  that  they  will 
reach  us  in  fresh  condition.  - 

Correspondents  can  materially  aid  the  work  of  this  depart- 
ment by  informing  it  of  their  success  or  failure  in  using  the 
methods  recommended  for  controlling  injurious  insects,  at  the 
same  time  giving  a  detailed  account  of  the  method  used  and 
the  results  obtained.  Such  information  will  prove  of  value  to 
all. 

SCALE  INSECTS. 

These  insects  are  among  the  most  dreaded  pests  on  fruit 
trees  in  the  State,  owing  to  their  prolificacy  and  easy  mode  of 
transportation.  They  are  generally  firmly 
attached  to  the  foliage  or  bark  of  trees,  and 
when  present  in  great  numbers  soon  kill 
the  plant  on  which  they  are  feeding. 

All  the  species 
in  our  orchards 
have  been  intro- 
duced. Although 
many  now  have 
their  natural 
enemies,  it  hav- 
ing been  the  pol- 
icy of  this  de-1 
partment  for ||| 
many  years  to 
control  these 
pests  by  their 
natural  para- 
sites, yet  it  is 
necessary,  in  abnormal  seasons,  to  use  artificial  means  to 
combat  them.  The  grower  very  often  overlooks  the  few  small 


FIG.  1.    San  Jose"  scale 
on  twig. 


FIG.  2.    Pear,  showing  effects  of 
San  Jos6  scale. 


INSECTS   AND    INSECTICIDES. 


specks  on  the  leaves,  fruit,  or  bark  of  his  trees  until  it  is  too 
late.  The  proper  time  for  effective  work  is  when  the  insects 
first  appear,  and  not  after  the  trees  are  half  killed  by  their 
attack. 

Nearly  all  species  of  scale  insects  can  be  killed  by  the  reme- 
dies recommended  in  this  bulletin,  but  some  species  have  to 
be  treated  by  fumigation  with  hydrocyanic  acid  gas;  especially 
is  this  true  on  evergreen  trees,  it  being  difficult,  owing  to  the 
dense  foliage,  to  reach  every  individual  by  sprays,  and  a  suffi- 
cient number  always  escape  to 
reinfest  the  trees.  Our  report 
for  1903-04  gives  a  list  of  scale 
insects  and  also  illustrates  many 
species  of  parasites  which  attack 
them,  colonies  of  which  will  be 
supplied  to  growers  on  applica- 
tion to  this  department. 

Following  are  the  sprays  rec- 
ommended for  the  various  scale 
insect  pests: 

Winter  Wash  for  San  Jose  Scale, 
Pear  Diaspis,  and  Greedy  Scale. — 
Following  is  the  lime-sulphur- 
salt  solution: 

Unslaked  lime 40  pounds. 

Sulphur 20  pounds. 

Stock  salt 15  pounds. 

Water,  to  make 60  gallons. 

Place  10  pounds  of  lime  and 
20  pounds  of  sulphur  in  a  boiler 
with  20  gallons  of  water,  and 
boil  over  a  brisk  fire  for  not  less 
than  one  hour  and  a  half,  or 

until  the  sulphur  is  thoroughly  dissolved.  When  this  takes 
place,  the  mixture  will  be  of  an  amber  color.  Next  place  in  a 
cask  30  pounds  of  unslaked  lime,  pouring  over  it  enough  hot 
water  to  thoroughly  slake  it;  and  while  it  is  boiling,  add  the 
15  pounds  of  salt.  When  this  is  dissolved,  add  to  the  lime 
and  sulphur  in  the  boiler,  and  cook  for  half  an  hour  longer, 
when  the  necessary  amount  of  water  to  make  the  60  gallons 
should  be  added. 


FIG.  3.    Brown  apricot  scale  (Euieca- 
nium  armeniacum,  Craw). 


6  STATE    HORTICULTURAL    COMMISSION. 

Rosin  Wash  for  all  Species  of  Scale  Insects  on  Deciduous  Trees. — 
The  following  are  the  proportions  of  materials  for  the  winter 
wash: 

Rosin    30  pounds. 

Caustic  soda  (98%) 8  pounds. 

Fish  oil 4^    pints. 

Water,  to  make 100  gallons. 

Place  the  rosin,  caustic  soda,  and  fish  oil  in  a  large  boiler, 
pour  over  them  about  20  gallons  of  water,  and  cook  thoroughly 
over  a  brisk  fire  for  at  least  three  hours;  then  add  hot  water,  a 
little  occasionally,  and  stir  well,  until  you  have  not  less  than 
50  gallons  of  hot  solution.  Place  this  in  the  spray  tank,  and 
add  cold  water  to  make  the  necessary  amount.  Never  add 
cold  water  when  cooking. 

Distillate  Spray  for  Young  Black  Scale  on  Orange  Trees. — To  be 

used  with  power  machine,  fitted  with  an  agitator,  speeded  at  65 
or  70  revolutions  per  minute: 

Distillate  28° 2  gallons. 

Water 100  gallons. 

Use  only  the  best  28°  distillate  and  see  that  a  perfect  mixture 
is  attained  at  nozzle  before  applying  to  trees.  This  can  be 
determined  by  agitating  for  a  sufficient  time  to  thoroughly  mix 
the  contents  of  tank;  the  time  will  vary  somewhat  according 
to  speed  and  construction  of  agitator.  Examine  the  mixture 
at  nozzle  by  holding  hand  in  front  of  same;  when  the  mixture 
is  at  its  whitest  it  is  ready  to  apply. 

When  engine  stops  from  any  cause,  immediately  discontinue 
application  of  spray.  When  starting  up  again,  empty  hose 
into  tank  until  the  mixture  is  again  at  its  whitest.  Apply 
spray  at  a  pressure  of  160  pounds. 

Do  not  spray  an  orchard  in  need  of  irrigation.  Trees  that 
are  not  in  a  thrifty  condition  should  be  sprayed  with  a  weaker 
solution. 

Avoid  spraying  during  the  prevalence  of  high  winds,  cold 
weather,  or  when  trees  are  wet  with  rain  or  fog. 

For  Red  Scale  increase  the  solution  to  2^  per  cent  on  orange 
and  to  2-2  per  cent  on  lemon  trees,  and  add  one  quart  of  pure 
turpentine  to  the  100-gallon  tank. 


INSECTS   AND   INSECTICIDES.  7 

Distillate  Emulsion  for  Black  Scale  on  Citrus  Trees. — The  follow- 
ing are  the  proportions  for  the  stock  solution: 

Distillate  28°  (untreated) 5   gallons. 

Hot  water. 5   gallons. 

Whale-oil  soap 1£  pounds. 

The  whale-oil  soap  must  first  be  dissolved  in  the  water.  Then 
add  the  dissolved  soap  to  the  distillate.  It  is  important  that 
the  distillate  be  placed  in  the  mixing  vessel  first,  then  place 
the  dissolved  soap  on  top.  Then  attach  the  spray  pump  to 
the  bottom  of  the  vessel  in  which  the  compound  is  being 
mixed,  and  keep  pumping  it  out  of  the  vessel  through  the  spray 
pump  and  back  into  the  vessel,  until  the  whole  becomes  of  a  rich 
creamy  substance.  Keep  pumping  or  churning  it  through  the 
pump  until  it  becomes  a  complete  emulsion,  without  a  speck 
of  free  oil  in  sight,  which  will  take  from  ten  to  fifteen  minutes. 
When  properly  emulsified,  it  should  increase  in  volume  about 
one  third,  because  it  becomes  aerified. 

After  the  stock  solution  has  been  thoroughly  prepared,  it 
will  readily  mix  with  cold  water.  To  each  gallon  of  the  above 
stock  solution  add  14  gallons  of  cold  water.  Always  place  the 
emulsion  in  the  spray  tank  first,  then  add  the  water,  as  by  this 
means  a  more  uniform  mixture  can  be  made.  This  emulsion 
can  be  applied  with  an  ordinary  hand  spray  pump. 

Summer  Wash  for  San  Jose  Scale  and  Other  Armored  Scales  on 
Deciduous  Trees. — Following  are  the  proportions  of  materials 
to  be  used: 

Whale-oil  soap 20  pounds. 

Sulphur . 3  pounds. 

Caustic  soda  98% 2  pounds. 

Water .100  gallons. 

Place  sulphur  and  caustic  soda  in  about  two  gallons  of 
water  and  boil  for  at  least  one  hour.  Dissolve  the  soap  by 
boiling  in  water.  Mix  the  two  solutions,  and  reboil  all  for  a 
short  time.  Apply  the  spray  warm. 

This  wash  also  makes  a  good  combination  spray  for  scale 
and  fungus. 

For  Individual  Trees  and  Shrubs  on  a  Small  Scale  use  the  fol- 
lowing: 

Whale-oil  soap 1  pound. 

Hot  water _. 5  gallons. 

Dissolve  the  soap  by  boiling,  and  apply  warm. 


8 


STATE   HORTICULTURAL   COMMISSION. 


Hydrocyanic  Acid  Gas  Treatment,  for  Destroying  Scale  Insects  on 
Citrus  Trees. — This  treatment  should  be  used  in  the  night  so  as 
to  avoid  light,  heat,  and  sea  breeze,  which  neutralize  the  effect 
of  the  gas.  The  chemicals  used  for  producing  the  gas  are: 
Sulphuric  acid  (commercial),  cyanide  of  potassium  (98%  to 
99%),  and  water. 

The  following  instructions  must  be  carefully  observed :  First, 
the  tent,  which  must  be  air-tight,  is  placed  over  the  tree; 
second,  the  tent  is  made  air-tight  around  the  bottom  by 
throwing  some  loose  soil  over  the  bottom  of  the  canvas;  third, 
the  necessary  amount  of  sulphuric  acid,  together  with  the 
required  amount  of  water,  is  put  in  a  glazed  earthenware  ves- 
sel, and  placed  under  the  canvas,  and  the  cyanide  of  potassium 
is  added.  A  piece  of  sacking  or  burlap  is  thrown  over  the  top 
of  the  vessel,  to  spread  the  gas  and  prevent  it  from  burning 
the  leaves  immediately  above  the  generator.  The  tree  is  left 
covered  forty  minutes. 

The  Riverside  County  Board  of  Horticultural  Commis- 
sioners recommends  the  following  proportions  of  chemicals: 


Height  of 
Tree. 

Diameter  of 
Tree. 

Water. 

Cyanide  C.  P.,  98 
per  cent. 

Sulphuric  Acid,  66 
per  cent. 

Feet. 

Feet. 

Ounces. 

Ounces. 

Ounces. 

6 

4 

2 

I 

1 

8 

6 

3 

u 

•             ty 

10 

8 

5 

2j 

2J 

12 

-14 

11 

5 

5j 

16 

16 

17 

8 

9W 

20 

16-20 

22 

10 

12 

20-24 

18-22 

30 

14 

16 

24-30 

20-28 

34 

16 

18 

30-36 

25-30 

52 

24 

28 

The  cyanide  should  be  used  about  the  size  of  walnuts,  so 
that  the  chemical  action  will  be  less  violent.  The  gas  is  also 
generated  more  evenly,  and  there  is  not  so  much  danger  of  the 
chemicals  boiling  over  or  spattering  the  tent.  As  soon  as  the 
tent  is  removed  :,the  vessel  is  rinsed  with  clean  water  and 
prepared  for  another  charge. 

APHIDS,:OR  PLANT  LICE. 

Next  to  the  scale  insects  are  the  aphids,  or  plant  lice,  as  they 
are  generally  called;  these  also  belong  to  the  sucking  insects. 

Plant  lice  are  small,  usually  green,  but  varying  to  brown  or 
black  insects,  and  are  generally  found  on  the  under  side  of 


INSECTS   AND   INSECTICIDES. 


leaves  or  on  growing  shoots.  These  insects  multiply  very 
rapidly,  but  fortunately  for  the  grower  the  hot  summer  climate 
of  California  prevents  long  duration  of  their  attack  and  there 
also  exist  in  California  hordes  of  natural  enemies  which  attack 
them  shortly  after  their  appearance  and  soon  reduce  their 
numbers. 

In  favorable  seasons,  however,  plant  lice  become  a  very  seri- 
ous pest  and  artificial  means  for  fighting  them  have  to  be 
resorted  to.  Near  y  all  varieties  of  fruit  trees  are  attacked  by 
them  and  a  great  many  of  our  early  fruits  are  rendered  unsal- 
able by  the  abundance  of  honey-dew  exuded  by  these  insects. 

The  principal  known  species  are: 

Woolly  Aphis  (Schizoneura  lanigera). — This  little  insect 
secretes  a  white  cottony  mass  about  its  body  and  infests  both 
the  roots  and  the 
branches  of  apple 
trees.  Its  presence 
can  be  readily  de- 
tected by  this  white 
cottony  mass,  and 
iipon  close  examina- 
tion the  brownish- 
pink  lice  are  found 
under  the  cotton.  The 
root  form  causes  great 
damage  to  the  tissues  of  the  roots  by  forming  swellings  or 
galls,  giving  an  unhealthy  growth,  which  soon  kills  the  small 
roots.  As  the  root-infesting  form  is  by  far  the  most  destruc- 
tive, it  is  important  that  remedial  measures  should  be  directed 
against  it.  By  eradicating  the  root  form  in  winter  a  great 
reduction  in  the  branch  or  aerial  form  follows,  but  it  can  be 
readily  understood  that  this  underground  form  is  extremely 
difficult  to  combat. 

Early  in  the  fall  dig  a  trench  around  the  tree,  uncovering 
the  crown  roots  as  much  as  possible;  in  this  trench  place  one 
or  two  shovelfuls  of  unslaked  lime,  according  to  the  age  and 
size  of  the  tree;  add  enough  water  to  slake  the  lime,  and  cover 
up  with  earth.  The  rain  will  keep  carrying  the  lime  to  the 
roots  and  reduce  the  pest.  As  a  substitute  for  the  unslaked 
lime,  gas  lime  is  very  often  used,  but  great  caution  must  be 


FIG.  4.    Woolly  Aphis  of  the  apple  (Schizoneura 
lanigera,  Hausm.) 


10  STATE   HORTICULTURAL    COMMISSION. 

exercised,  for  if  applied  in  too  great  quantity  there  is  danger 
of  killing  the  tree.  One  or  two  shovelfuls  can  be  used  on  an 
old  tree,  but  a  young  tree  should  not  be  treated  with  this 
substance. 

The  use  of  tobacco  dust  has  given  good  results,  particularly 
on  young  trees  and  nursery  stock.  The  application  should  be 
made  in  the  fall  of  the  year,  so  that  the  rains  can  leach  out  the 
tobacco  juice  and  bring  it  in  contact  with  the  aphids. 

For  the  branch,  or  aerial,  form  a  good  kerosene  emulsion 
or  whale-oil  soap  wash  (summer  formula)  will  soon  reduce 
the  pest. 

KEROSENE  EMULSION. 

Coal  oil  (150°  test) 4  gallons. 

Laundry  soap 1  pound. 

Water . 2  gallons. 

Dissolve  the  soap  by  boiling  in  the  water,  and  when  dissolved 
and  while  boiling  pour  with  a  dash  into  the  kerosene.  Churn 
the  mixture  for  ten  or  fifteen  minutes,  either  by  pouring  back 
and  forth  from  one  vessel  to  another,  or  by  pumping  the  liquid 
back  upon  itself.  The  emulsion  should  have  the  consistency 
of  cream. 

For  a  winter  wash  when  trees  are  dormant,  use  one  gallon  of 
emulsion  to  six  gallons  of  hot  water. 

For  a  summer  wash  use  one  gallon  of  emulsion  to  ten  gallons 
of  hot  water. 

Prune  Aphis  (Aphis  prunifolias) . — These  insects  are  readily 
recognized  by  their  bluish-green  color 
and  by  the  abundance  of  honey-dew 
—  generally  found  on  the  ground  under 
the  infested  trees.  In  abnormal  ,sea- 
sons  only  does  this  pest  become  inju- 
rious to  the  prune  trees.  Our  native 
lady-birds  and  syrphus  flies  generally 
keep  this  species  under  control,  but 
in  the  absence  of  these  friends  use  the 
summer  formula  of  the  kerosene 

FIG.  5.  Prune  Aphis  (Aphis     emulsion  or  the  whale-oil  soap  solu- 

prunifolise), 

tion. 

Black  Peach  Aphis  (Aphis  persicte-niger). — This  insect  is 
one  of  the  most  dangerous  foes  of  the  peach  tree,  and  the 
grower  should,  at  the  very  start,  wherever  he  notices  its 


INSECTS   AND   INSECTICIDES.  11 

appearance,  thoroughly  eradicate  it.  It  is  a  small  brownish- 
black  insect  and  exists  in  the  wingless  as  well  as  in  the  winged 
form.  It  attacks  the  roots  as  well  as  the  foliage,  and  this 
makes  it  all  the  more  diffi- 
cult to  combat.  The  branch 
form  is  readily  controlled 
by  the  use  of  kerosene 
emulsion  or  the  whale-oil 
soap  wash,  using  the  sum- 
mer formula;  but,  so  far, 
no  wash  or  remedy  has 
been  found  to  give  perfect  FlG  6  Black  p~ch  Aphis  (Aphis 

results    On    the    root    form,  perslcx-niger). 

only  partial   relief   having 

been  obtained  by  the  use  of  a  diluted  kerosene  emulsion,  used 
around  the  base  of  the  tree  and  applied  during  or  just  before 
a  rain.  This  allows  the  water  to  carry  the  emulsion  to  the 
infested  parts.  Tobacco  dust,  as  recommended  for  the  root 
form  of  woolly  aphis,  will  also  give  partial  relief. 

Hop  Louse  (Phorodon  humuli). — The  following  is  recom- 
mended, to  be  applied  as  a  spray: 

Whale-oil  soap 7  pounds. 

Quassia  chips .-_ 8  pounds. 

Water 100  gallons. 

Soak  the  quassia  chips  for  eight  or  nine  hours  in  hot  water. 
Dissolve  the  whale-oil  soap,  by  boiling,  and  mix  the  two 
liquids,  adding  enough  water  to  make  100  gallons. 

The  best  machine  to  use  is  the  Knapsack  sprayer  with  a 
Cyclone  or  Vermorel  nozzle,  using  a  very  fine  spray  and 
applying  it  to  the  under  side  of  the  foliage. 

CANKER     OR     MEASURING    WORMS,    TUSSOCK    MOTH,    LEAF- 
ROLLERS,  AND  OTHER  LEAF-EATING  CATERPILLARS. 

For  these  pests  the  following  is  recommended: 

Arsenate  of  lead 12  pounds. 

Water 200  gallons. 

Rub  up  the  desired  quantity  of  arsenate  of  lead  into  a 
smooth,  thin  paste  in  a  small  amount  of  water,  and  pour  into 
the  spraying  tank  or  barrel.  Keep  the  mixture  well  stirred 
and  use  a  fine  spray  with  plenty  of  pressure.  A  warm,  sunny 
day  should  always  be  selected. 


12 


STATE    HORTICULTURAL    COMMISSION. 


Cankerworms. — Two  species  of  cankerworms  do  damage  to 
our  trees,  but  they  so  closely  resemble  each  other  that  it  is 
difficult  to  distinguish  them  in  the  larval  form.  The  adult 
moths,  male  and  female,  do  not  resemble  each  other,  the  male 
being  winged,  the  female  wingless.  The  proper  time  for  fight- 
ing this  pest  is  when  the  wingless  female  makes  her  appearance 
out  of  the  ground  where  she  has  been  hibernating  in  the  pupal 
form.  For  years  many  devices  have  been  used  to  prevent  the 

female  from  ascending  the 
tree,  and  any  substance 
which  will  retain  its  sticki- 
ness will  be  good  for  this 
purpose.  During  1905  ex- 
tensive experiments  were 
carried  on  with  tree  tangle- 
foot, a  very  sticky  sub- 
stance manufactured  in 
the  East.  The  results  were  very  gratifying;  in  fact,  tests  were 
made  side  by  side  with  the  wire-mesh  trap,  and  the  tanglefoot 
gave  by  far  the  better  results.  The  substance  should  be  ap- 
plied in  early  November,  and  is  put  on  a  paper  band  which 


FIG.  7.  Spring  Cankerworm  (Paleacrita  vernata). 
a.  Male  moth.  6.  Female  moth.  c.  Three 
joints  of  antennae  of  female  moth.  d.  Abdom- 
inal segment  of  female  moth,  enlarged. 
e.  Ovipositor,  enlarged. 


a-"*i&P  e 

FIG.  8.    Fall  Cankerworm  (Alsophila  pometaria). 

a.  Male  moth.  6.  Female  moth.  c.  Joints  of  antennae  of  female, 
enlarged,  d.  Segment  of  body  of  female,  enlarged,  e.  Larvae  of 
cankerworm. 

has  been  fastened  to  the  tree,  and  when  the  wingless  moth 
crawls  upon  it  she  is  held  captive  and  soon  perishes. 

If  through  neglect  in  banding  the  trees  the  moths  ascend  to 
the  branches  and  deposit  their  eggs,  producing  a  brood  of 
worms,  the  only  remedy  is  the  arsenate  of  lead  solution. 

Tussock  Moth  (Hemerocampa  vetusta,  Boisd.). — The  larva  of 
this  moth  does  not  form  a  tent,  as  in  the  case  of  the  forest-tent 
caterpillar,  which  is  often  taken  for  it.  It  is  generally  found 
singly  on  the  under  side  of  leaves,  or  along  the  stems  of  new 
growth,  and  is  a  very  general  feeder.  Gathering  the  white, 


INSECTS    AND    INSECTICIDES. 


13 


woolly  egg-clusters  in  pruning  season  has  proved  very  success- 
ful in  combating  this  pest  in  certain  sections,  while  in  other 


FIG.  9.    Tussock  Moth,  caterpillar. 


b 

Fio.  10.    Tussock  Moth. 

a.  Female  moth.    ft.  Young  larva,    c.  Female  pupa. 
d.  male  pupa. 


FIG.  11.    Tussock 
Moth,  male. 


sections  it  is  held  in  check  by  parasites  which  attack  these  egg- 
clusters.  In  very  badly  infested  orchards  spraying  can  be 
resorted  to,  and  the  arsenate  of  lead  solution  will  be  found  a 
good  remedy. 

Tent  Caterpillars. — These  caterpillars  are  at  times  very  abun- 
dant  and   cause   a   great   deal    of    damage   to  the   foliage  of 


Female  moth.  Larva. 

FIG.  12.    Tent  Caterpillar  (CIMocampa  tylvatirci). 

fruit  trees.  The  presence  of  the  caterpillars  can  easily  be 
detected  by  the  tents  or  webs  which  the  colony  of  worms  spin 
in  the  tops  of  the  trees.  Collecting  and  burning  these  tents, 


14  STATE   HORTICULTURAL   COMMISSION. 

in  which  the  caterpillars  rest  during  the  day,  is  about  the 
quickest  and  best  method  to  check  their  ravages. 

Leaf-Rollers  (Cacoecia  sp.). — These  caterpillars  are  gener- 
ally concealed  in  a  few  leaves  rolled  together,  and  feed  at  night. 
They  have  been  known  to  do  a  great  deal  of  damage  in  favor- 
able seasons,  and  very  often  have  been  taken  for  cankerworms, 
but  the  dark  green  color  with  a  black  head  and  the  non-loop- 
ing movement  of  the  body  correct  this  error.  In  orchards 
where  spraying  with  paris  green  or  other  arsenates  is  done 
this  pest  soon  disappears,  as  any  arsenate  spray,  by  poisoning 
the  leaves,  will  soon  reach  it. 

CUTWORMS  AND  GRASSHOPPERS. 

The  following  poison  bait  is  recommended : 

Bran . 40  pounds. 

Middlings 20  pounds. 

White  arsenic 20  pounds. 

Cheap  molasses .......  2  gallons. 

Thoroughly  mix  the  bran,  middlings,  and  arsenic  together 
dry,  then  add  two  gallons  of  cheap  molasses  and  sufficient 
water  to  make  the  whole  into  a  crumbling  moist  mash.  Place 
a  tablespoonful  of  the  mixture  a  few  inches  from  the  tree 
or  vine. 

Cutworms  (Peridroma  saucia  and  Agrotis  spp.).— Cutworms 
are  the  larvae  or  caterpillars  of  owlet  moths.  They  feed  at 
night,  resting  underground  during  the  day.  Their  natural 
food  is  weeds,  clover,  grasses,  etc.  In  wet-  seasons,  when  weeds 
are  abundant,  cutworms  are  found  in  great  numbers,  and 
when  the  grower  turns  under  the  weeds,  depriving  the  worms 
of  their  natural  food,  they  will  attack  cultivated  plants, 
trees,  and  vines.  The  most  successful  way  of  fighting  cut- 
worms is  to  place  a  poisoned  food  wherever  this  pest  is  doing 
damage,  care  being  taken  not  to  allow  livestock  or  poultry  to 
run  where  the  poison  is  placed.  Alfalfa  or  any  succulent 
vegetable,  such  as  cabbage  or  lettuce,  can  be  dipped  in  a  strong 
solution  of  arsenic  and  water  and  placed  on  the  ground  around 
the  damaged  plants,  but  the  bran-and-arsenic  remedy  given 
above  is  more  generally  used. 

It  has  been  found  that  their  numbers  can  be  greatly  dimin- 
ished and  the  loss  from  their  depredations  materially  checked 


INSECTS   AND   INSECTICIDES.  15 

by  gathering  the  worms  by  jarring  the  vines  over  canvas  sheets 
and  collecting  them  while  hoeing  the  weeds  around  the  vines. 

Grasshoppers. — Grasshoppers  appear  periodically  in  large 
swarms  and  farmers  are  at  a  loss  to  know  what  to  do.  This  is 
generally  the  case  when  the  insects  are  on  the  wing,  at  which 
time  it  is  almost  impossible  to  combat  them.  The  proper  time 
to  eradicate  a  swarm  of  grasshoppers  is  when  they  are  in  the 
nymph  or  wingless  stage,  at  which  period  they  are  slow  of 
motion  and  can  be  driven  on  to  any  kind  of  dry  material  and 
destroyed  by  burning.  Grasshoppers  generally  breed  in  pas- 
ture lands  or  uncultivated  fields  near  cultivated  areas,  and  as 
the  pastures  dry  up  they  migrate  to  the  cultivated  fields.  It 
is  absolutely  necessary  to  check  this  wandering  before  the 
insects  develop  wings.  A  great  many  devices  have  been 
invented  to  prevent  them  from  entering  cultivated  grounds,, 
and  by  the  use  of  smudges  swarms  have  been  scattered,  but 
these  methods  have  generally  been  used  on  prairie  lands.  If 
the  pasture  lands  are  beginning  to  dry  up  and  the  young 
hoppers  are  starting  to  move,  a  very  successful  attack  can  be 
made  by  using  the  poison,  bait  recommended  herein. 

FLAT-HEADED  APPLE-TREE  BORER  (Chrysobothrys  femorata). 

Whenever  fruit  trees  become  burned  they  at  once  become 
infested  with  the  flat-headed  borer,  a  yellowish-white  grub, 
with  large,  flat  head,  the  larva  of  the 
beetle.  All  trees,  when  planted, 
should  be  placed  as  nearly  as  possible 
as  they  stood  in  the  nursery,  for  by 
reversing  the  north  side  to  the  south 
they  invariably  become  sunburned.  Beetle.  Larva. 

Tree-protectors  or  a  good  whitewash       FlG-  18-  Fiat-Headed  Apple- 
Tree  Borer, 
will  prevent  this  trouble,  if  used  in 

time.     If  borers  infest  a  tree,  they  must  be  removed  and  the 
trunk  of  the  tree  painted  with  the  following  solution : 

Unslaked  lime 50  pounds. 

Whale-oil  soap 12  pounds. 

Slake  the  lime  with  sufficient  water  to  make  a  thick  white- 
wash; dissolve  the  whale-oil  soap  by  boiling,  and  add  this  to 
the  lime,  mixing  it  thoroughly;  the  whole  should  have  the 
consistency  of  cream.  Apply  to  the  trunks  of  sunburned  trees. 


16  STATE   HORTICULTURAL   COMMISSION. 

PEACH-TREE  BORER  (Sanninoidea  opalescens). 

The  larva  of  this  insect  is  a  pale-yellowish,  cylindrical  grub, 
nearly  an  inch  in  length,  and  very  destructive  to  the  lower 
^trunk  and  roots  of  peach,  almond,  apricot,  prune,  and  cherry 
trees.  Many  devices  and  remedies  have  been  used  to  check  its 
work,  but  none  have  proven  entirely  satisfactory.  The  worm- 
ing or  digging-out  method,  although  very  expensive,  is  no 
doubt  the  most  reliable  one,  and  when  followed  by  the  appli- 


Female.  •  Male- 

Pupa. 
FIG.  14.    Peach -root  Borer  (Sanninoidea  opale*ce»x). 

cation  of  a  barrier,  or  preventive,  to  keep  out  the  new  brood, 
which  is  absolutely  necessary,  has  given  good  results. 

In  the  digging-out  method,  the  earth  should  be  removed 
from  around  the  tree  and  wherever  gum  is  found,  the  borer 
chisel  should  be  carefully  used  and  the  borers  removed,  care 
being  taken  not  to  remove  too  much  bark.  The  proper  time 
to  do  this  is  in  November,  December,  or  January.  After  the 
trees  have  been  thoroughly  gone  over,  a  barrier  compound 
should  be  applied.  The  following  two  mixtures  have  given 
good  results: 

Mixture  No.   1. 

Unslaked  lime 50  pounds. 

Whale-oil  soap . 12  pounds. 

Coal  tar 1J  gallons. 

To  make  the  compound,  slake  the  lime  and  tar  together, 
adding  enough  water  to  make  a  medium  thick  whitewash. 
Dissolve  the  soap  with  hot  water  and  add  this  to  the  lime 
solution,  using  enough  water  with  the  mixture  to  make  a 
thick,  paste-like  whitewash. 

Mixture  No.  2. 

Unslaked  lime 50  pounds. 

Crude  oil,  16°  Beaume  ... ' 3  gallons. 

Slake  the  lime  and  crude  oil  together,  adding  enough  water 
to  make  a  thick  whitewash. 

The  application  of  crude  oil  alone  (14°  or  16°  Beaume)  will 


INSECTS   AND   INSECTICIDES. 


17 


successfully  drive  out  or  kill  the  small  borers,  but  does  not 
seem  to  affect  those  that  are  full  grown.  The  constant  appli- 
cation of  crude  oil  alone  to  trees,  especially  in  warm  localities, 
should  be  avoided,  as  experience  has  shown  that  it  is  detri- 
mental to  the  bark. 

STRAWBERRY  AND  CURRANT  BORERS. 

These  pests  usually  attack 
old  plantings.  The  best  rem- 
edy for  the  strawberry  borer 
is  to  dig  up,  as  soon  as  discov- 
ered, the  plants  showing  in- 
festation. In  the  case  of  the 
currant  borer,  the  infested 
canes  should  be  carefully  re- 
moved below  the  point  of 
infestation  and  immediately 
burned. 

PEACH  MOTH  (Anarsia  lineatella}. 

The  sudden  wilting  of  the  young,  tender  growth  of  peach, 


Pupa  and  Larva.  Moth. 

FIG.  15.    The  Currant  Borer  (JEgeria 
tipuliformis). 


FIG.  16.    Peach  Moth  (Anarsia  linealella). 
a.  Moth  with  spread  wings,    b,  c.    Same  with 
wings  closed,  illustrating   positions  normally 
assumed.    All  much  enlarged.    (After  Marlatt.) 


FIG.  17.    Peach  Moth  (Anarsia 
lineatella). 

a.  Egg.  6.  Young  larva,  c.  Eye. 
d.  Thoracic  leg  of  same.  e.  Anal 
segment  from  above.  All  greatly 
enlarged.  (After  Marlatt.) 


apricot,  and  prune  trees  is  caused  by  a  small  reddish-brown 
worm,  the  larva  of  the  peach  moth.     This  worm  hibernates 


18 


STATE   HORTICULTURAL   COMMISSION. 


during  the  winter  months  in  the  soft  bark  of  the  crotch  of  the 
tree,  and  can  be  killed  by  the  use  of  the  lime-sulphur-salt 
solution,  or  by  a  good  kerosene  emulsion.  Care  should  be« 
taken  to  select  sunny  weather  and  spraying  should  be  put  off 
as  late  as  possible,  preferably  just  before  the  swelling  of  the 
buds.  Either  spray  will  penetrate  the  burrows  and  kill  the 
small  worm. 

CODLING-MOTH  ( Carpocapsa  pomonella. ) 

The  larva?  of  the  codling-moth,  or  worm  of  the  apple,  pos- 
sibly do  as  much 
damage  to  the  ap- 
ple and  pear  crops 
in  this  State  as 
anything  which 
attacks  fruit  trees. 
Thorough  spray- 
\W  inti;.  dean  culture, 
and  collecting  all 
fallen  fruit  go  far 
toward  coping 
with  the  pest.  The 
newly  introduced 
parasite,  Calliephisetes  messer,  Grav.,  has  already  taken  hold 
of  this  pest  in 
several  sections 
and  may  prove 
a  great  aid  in 
keeping  it  in 
check  in  the 
future.  During 
the  present  sea- 
son the  arse- 
nate  of  lead 
seems  to  be  the 
leading  spray 
material  in  use, 
owing  to  its  ad- 
hesive properties.  This  material  in  a  prepared  form  and 
ready  for  use  simply  by  the  addition  of  water  in  sufficient 
quantity,  is  on  the  market  in  different  sized  packages.  A 


FIG.  18.    Codling-Moth  (Carpocapsa  pomonella), 
larvae  in  apple. 


^^'ffX^ 


FIG.  19.    Codling-Moth  (Carpocapsa  iiomonella). 
Showing  variations.    All  natural  size. 


INSECTS   AND   INSECTICIDES.  19 

great  deal  of  disappointment  in  the  use  of  paris  green  gener- 
ally occurs,  on  account  of  either  poor  material  or  unfavorable 
weather  conditions.  The  weather  does  not  seem  to  have  the 
same  effect  on  the  arsenate  of  lead  as  it  does  on  other  sprays, 
and  storms  do  not  seem  to  remove  this  poison,  as  it  is  not  sus- 
ceptible to  the  rain. 

Mixture  No.  1. 

Arsenate  of  lead ..  8  to  12  pounds. 

Water 200  gallons. 

Make  the  arsenate  of  lead  into  a  smooth,  thin  paste  by  using 
the  necessary  amount  of  water,  then  pour  into  the  spray  tank, 
and  keep  well  stirred  while  spraying.  Use  a  fine  spray  with 
plenty  of  pressure. 

Mixture  No.  2. 

Paris  green 1  pound. 

Unslaked  lime 6  pounds. 

Water 200  gallons. 

Make  the  paris  green  into  a  paste  before  placing  it  in  the 
spray  tank.  Slake  the  lime  with  plenty  of  water  and  strain 
thoroughly  so  as  to  eliminate  all  particles  which  might  clog  up 
the  nozzle.  Place  the  lime  solution  and  paris  green  in  the 
tank  with  the  water  and  stir  the  mixture  constantly  while 
spraying.  Lime  water  alone  has  been  used,  but  it  is  preferable 
to  use  the  lime,  as  it  shows  when  the  trees  have  been  sprayed 
thoroughly. 

PEAR   OR   CHERRY   SLUG  (Eriocampa  cerasi). 

When  the  pest  first  makes  its  appearance,  especially  on 
young  trees,  a  good  dusting  with  air-slaked  lime  or,  better, 
hydrated  lime,  will  check  the  damage.  Spraying  with  arsenate 
of  lead,  as  recommended  for  cankerworms,  will  be  found  very 
efficient  on  larger  trees. 

CABBAGE    WORMS,    CUCUMBER    BEETLES,    DIABROTICA,    AND 
FLEA  BEETLES. 

The  following  are  recommended: 
Wet  Sprays. 

(1)  Arsenate  of  lead 6  to  8  pounds.      (2)  Paris  green 1  pound. 

Water 100  gallons.  Unslaked  lime 2  pounds. 

Water 160-200  gallons. 

Dry  Sprays. 

(1)  Paris  green 1  pound.        (2)  White  arsenic 1  pound. 

Hydrated  lime,  air-  Hydrated  lime,  air- 
slaked  lime,  or  wheat  slaked  lime,  or  wheat 
flour 10  pounds.  flour 12  pounds. 


20  STATE   HORTICULTURAL   COMMISSION. 

Both  the  wet  and  the  dry  sprays,  when  thoroughly  mixed, 
will  be  found  very  efficient  in  eradicating  these  pests  by  either 
dusting  with  the  dry  compound  or  spraying  in  the  regular 
manner  with  the  wet  solution. 

SQUASH    BUG    (Anasa  triatis)',    HARLEQUIN   CABBAGE  BUG    (Mur- 
gantiahistrionica)',  BOX  ELDER  PLANT  BUG  (Leptocoris  triri.ttatus). 

These  insects  are  too  well  known  to  need  description.  The 
females,  which  hibernate  during  winter  in  dried  leaves  and 
weeds  along  fences,  lay  their  eggs  on  the  under  side  of  the 
leaves  or  on  the  stems  of  young  plants.  To  be  successful  in 
fighting  these  pests  the  hibernating  females  must  be  gathered 
before  they  lay  their  eggs,  thus  preventing  the  spring  brood 
from  making  its  appearance.  This  has  been  done  on  a  large 


FIG.. 20.    Harlequin  Cabbage  Bug  (Murgantia  histrionica). 

a.  Larva,     b.  Pupa.    c.  Eggs,  natural  size.     d.  Eggs,  enlarged,      e.  Eggs  seen  from 

above, enlarged. 

scale  and  is  the  only  true  way  of  preventing  the  enormous 
increase  which  generally  occurs  where  these  pests  are  let  alone. 
In  case  the  spring  brood  makes  its  appearance,  about  the  only 
available  method  is  hand  picking  or  jarring  them  into  recepta- 
cles containing  kerosene.  Where  the  pest  is  very  numerous 
the  planting  of  early  trap  crops  has  also  been  found  quite 
successful. 

HESSIAN  FLY  (Cecidomyia  destructor}. 

This  is  one  of  the  pests  which,  in  favorable  seasons,  appear 
in  our  grain  fields  and  it  does  considerable  damage  to  the  grow- 
ing grain.  The  adult  fly  is  a  small  black  gnat,  resembling 
somewhat  the  mosquito  on  a  very  small  scale.  The  female 
deposits  her  eggs  on  the  leaves  and  leaf-stalks  of  the  sprouting 
grain.  These  eggs,  which  are  very  minute,  are  pale  orange  in 
color,  with  reddish  dots,  and  are  laid  with  the  head  end 
downward.  As  soon  as  the  tiny  grub  hatches,  it  goes  down  the 
stem  and  forces  itself  between  the  stem  and  the  sheath  as  near 
the  joint  as  possible.  At  this  point  the  grub  makes  its  attack 


INSECTS   AND   INSECTICIDES.  21 

by  sucking  the  sweet  juices  of  the  stalk,  which  soon  wilts  and 
falls  over.  After  the  grub  has  attained  its  full  growth  it 
passes  into  a  brown  pupa  form,  which  resembles  a  flax  seed, 
and  the  empty  pupa  case  is  left  protruding  from  the  stalk 
after  the  fly  has  emerged. 

Where  this  pest  has  appeared  it  is  advisable  to  burn  off  the 
stubble  in  the  fall,  as  this  will  destroy  the  " flax-seed"  pupae, 
which  hibernate  in  the  stubble.  It  is  also  advisable  to  sow 
the  grain  as  late  as  possible. 

GARDEN  SLUGS  OR  SNAILS. 

Although  slugs  or  snails  do  not  belong  to  the  same  sub-king- 
dom as  insects,  yet  the  damage  which  some  of  them  inflict  on 
vegetables  and  other  products  of  the  gardener  and  florist  is 
sufficient  to  cause  mention  of  these  pests  in  this  bulletin.  They 
are  generally  found  in  damp  places,  hiding  under  stones  and 
in  cracks  of  the  ground  in  daytime.  In  the  evening  they  come 
from  their  hiding  places  in  search  of  food,  and  as  they  are 
voracious  feeders,  they  often  do  great  damage. 

At  sundown  thoroughly  drench  the  garden.  Place  pieces  of 
board,  shingles,  or  even  cabbage  leaves  on  the  beds  where  the 
damage  has  been  done.  The  slugs  will  congregate  on  the  under 
side  of  these  traps  instead  of  returning  into  the  wet  soil  and 
can  easily  be  killed  in  the  morning.  Spreading  fresh  slaked 
lime  on  the  ground  around  the  plants  that  have  been  attacked 
will  act  as  a  repel] ant,  but  if  much  watering  is  done  the  lime 
will  soon  be  washed  away. 

RED  SPIDERS  AND  MITES. 

Red  spiders  appear  as  minute  red,  reddish-brown,  or  yellow 
specks  on  either  the  surface  or  the  under  side  of  the  leaves  and 
by  the  aid  of  a  hand  lens  are  easily  recognized.  The  eggs 
are  generally  laid  in  masses  on  the  un'der  side  of  branches  and 
around  the  buds,  this  being  particularly  true  of  the  almond 
bryobia.  The  damage  done  by  these  minute  creatures  can 
easily  be  noticed.  The  mites  suck  the  sap  from  the  cells  of 
the  leaves,  which  take  on  a  pale  color  and  finally  drop  to  the 
ground.  The  following  remedies  have  been  used  to  advantage: 

For  Red  Spider  or  Yellow  Mite  on  Deciduous  Trees. — Soon  after 
the  trees  are  in  leaf  in  the  spring,  and  while  they  are  damp 


22  STATE   HORTICULTURAL   COMMISSION. 

with  dew  in  the  morning,  thoroughly  dust  them  with  sulphur. 
Use  sulphur  bellows,  or  if  the  orchard  is  extensive,  fix  up  a 
broadcast  seeder  on  a  wagon.  With  this  arrangement  an 
orchard  can  be  treated  very  thoroughly  and  with  dispatch. 
Infested  orchards  should  be  treated  at  least  three  times  during 
the  spring  and  early  summer. 
'  While  this  is  true  generally,  sometimes  the  dry  sulphur  does 


FIG.  21.    Yellow  Mite.  FIG.  22.    Pear-Leaf  Blister  Mite  (Phytoptuspyri),  very 

greatly  enlarged. 

not  seem  to  do  the  work,  owing  to  climatic  conditions,  and  it  is 
best  to  apply  the  sulphide  of  potash  wash,  as  follows: 

Caustic  soda  98% 10  pounds. 

Sulphur. __         20pounds. 

Dissolve  in  water 20  gallons. 

Take  the  sulphur,  mix  it  to  a  paste — not  sloppy — with  cold 
water  in  a  barrel,  then  add  to  this  wet  sulphur  10  pounds  of 
caustic  soda  (98  per  cent),  and  it  will  boil  the  sulphur  just  like 
lime  slaking;  have  20  gallons  of  water  to  add  to  it  as  it  boils, 
to  prevent  its  burning.  This  is  the  stock  solution,  and  when 
ready  to  spray  the  mites  or  spiders,  put  40  gallons  of  water  in 
another  barrel,  and  take  a  half  gallon  of  the  stock  solution 
and  add  to  the  40  gallons  of  water,  straining  it  to  take  out  any 
sediment  there  may  have  been  in  the  sulphur.  Remember, 
this  is  for  mites  and  spiders  only.  This  stock  solution  should 
be  diluted  one-half  gallon  to  40  gallons  of  water,  and  applied 
with  a  spray  pump  under  100  pounds  pressure. 

The  distillate  spray  of  2  per  cent  strength  with  the  addition 
of  7  pounds  of  flour  of  sulphur  has  proved  very  effective  in 
some  sections  of  the  State.  To  use  the  sulphur  in  this  mixture, 
it  is  necessary  to  first  make  a  paste  of  the  sulphur  before  adding 
it  to  the  distillate  mixture. 

For  Pear-leaf  Blister  Mite,  Walnut-leaf  Blister  Mite,  Grape-leaf 
Mite,  Orange  and  Lemon  Peel  Mites. — The  burrowing  mites,  or 
Phytopti,  differ  from  all  the  other  mites  in  having  but  two 


INSECTS   AND   INSECTICIDES.  23 

pairs  of  legs,  always  located  near  the  head  (see  figure),  whereas 
the  "red  spider"  (Tetranychus)  has  three  pairs  in  the  young 
stage  and  four  pairs  in  the  adult,  located  upon  the  sides. 
The  body  of  the  Phytoptus  is  cylindrical,  transparent,  and 
long,  as  compared  with  the  other  portions  of  the  mite.  From 
the  position  of  the  legs  it  has  to  drag  its  body  in  walking. 

Kerosene  emulsion  is  considered  the  most  effective  wash  for 
winter  use.  It  is  very  effective  when  diluted  with  from  three 
to  eight  parts  of  water  and  sprayed  on  the  infested  trees  or 
vines  before  the  leaves  start.  Trees  sprayed  with  the  strongest 
solution  are  practically  free  from  this  pest.  Those  sprayed 
with  the  weaker  solution  show  very  few  galls — not  over  one 
per  cent  of  the  number  that  were  on  the  trees  the  preceding 
year.  Summer  treatment  with  liquid  remedies  is  of  little  avail. 
As  soon  as  the  leaves  start  in  the  spring  they  should  be  liber- 
ally treated  with  dry  sulphur  in  the  early  morning  while  yet 
damp  with  dew;  a  second  and  third  application  as  the  growth 
develops  will  be  found  effective. 


14  DAY  USE 

RETURN  TO  DESK  FROM  WHICH  BORROWED 


is  book  is  due  "on  the  last  date  stamped  below,  or 

on  the  date  to  which  renewed. 
Renewed  books  are  subject  to  immediate  recall. 


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LD  21-40m-l,'68 
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